Insect bite dermatitis, contact dermatitis, folliculitis, eczema, etc. may occur. 1. Insect bite dermatitis: after mosquito bites, small red dots may appear, mostly accompanied by itching or pain, and if not treated in time, there will be surrounding skin progressive growth of small red dots. 2. Contact dermatitis: some people in contact with some allergens or irritants, can be manifested as long as small red dots, with itching, if you do not keep away from the allergens or irritants, will continue to grow small red dots. 3. Folliculitis: If you don’t pay attention to the hygiene of the skin, it may cause bacterial or fungal infections, and follicular pimples gradually appear all over the body, accompanied by a certain itching sensation. 4. Eczema: Eczema patients will also be manifested in the gradual appearance of small red spots, accompanied by itching. There may be other causes of the above situation, it is recommended to go to the hospital in time to identify the cause, symptomatic treatment.